Landmarks in the historical development of twenty first century food processing technologies

Ultrasound processing of fresh and frozen semi-skimmed sheep milk and its effects on microbiological and physical-chemical quality

The objective of this study was to evaluate the effect of ultrasound treatment on the microbiological quality, protein and free amino acid profile of fresh and frozen stored semi-skimmed sheep milk. Milk was treated as fresh or frozen and stored up to one, three and six months. Output power time and pulse time were the parameters combined to design four different ultrasound (US) treatments: power 78 W and duration 6 min (US1); power 78 W and duration 8 min (US2); power 104 W and duration 4 min (US3) power 104 W and duration 6 min (US4). Pulse duration was of 4 s for each treatment. Sample US1 was discarded due to non effectiveness of US treatment, while other samples showed interesting results. Also, it was verified a frost effect on microorganisms in all samples which were frozen before treatment. No relevant change was reported on amino acid profile. The study showed promising results: the ultrasound treatment inactivated or eliminated the studied contaminant bacteria in semi-skimmed sheep milk, while maintained acceptable amount of lactic bacteria, which could be advantageous for dairy products processing.

Innovative processing techniques for altering the physicochemical properties of wholegrain brown rice (Oryza sativa L.) - opportunities for enhancing food quality and health attributes

Rice is a globally important staple consumed by billions of people, and recently there has been considerable interest in promoting the consumption of wholegrain brown rice (WBR) due to its obvious advantages over polished rice in metabolically protective activities. This work highlights the effects of innovative processing technologies on the quality and functional properties of WBR in comparison with traditional approaches; and it is aimed at establishing a quantitative and/or qualitative link between physicochemical changes and high-efficient processing methods. Compared with thermal treatments, applications of innovative nonthermal techniques, such as high hydrostatic pressure (HHP), pulsed electric fields (PEF), ultrasound and cold plasma, are not limited to modifying physicochemical properties of WBR grains, since improvements in nutritional and functional components as well as a reduction in anti-nutritional factors can also be achieved through inducing related biochemical transformation. Much information about processing methods and parameters which influence WBR quality changes has been obtained, but simultaneously achieving the product stabilization and functionality of processed WBR grains requires a comprehensive evaluation of all the quality changes induced by different processing procedures as well as quantitative insights into the relationship between the changes and processing variables.

Food processing: criteria for dietary guidance and public health?

The NOVA food categorisation recommends ‘avoiding processed foods (PF), especially ultra-processed foods (UPF)’ and selecting minimally PF to address obesity and chronic disease. However, NOVA categories are drawn using non-traditional views of food processing with additional criteria including a number of ingredients, added sugars, and additives. Comparison of NOVA's definition and categorisation of PF with codified and published ones shows limited congruence with respect to either definition or food placement into categories. While NOVA studies associate PF with decreased nutrient density, other classifications find nutrient-dense foods at all levels of processing. Analyses of food intake data using NOVA show UPF provide much added sugars. Since added sugars are one criterion for designation as UPF, such a proof demonstrates a tautology. Avoidance of foods deemed as UPF, such as wholegrain/enriched bread and cereals or flavoured milk, may not address obesity but could decrease intakes of folate, calcium and dietary fibre. Consumer understanding and implementation of NOVA have not been tested. Neither have outcomes been compared with vetted patterns, such as Dietary Approaches to Stop Hypertension, which base food selection on food groups and nutrient contribution. NOVA fails to demonstrate the criteria required for dietary guidance: understandability, affordability, workability and practicality. Consumers’ confusion about definitions and food categorisations, inadequate cooking and meal planning skills and scarcity of resources (time, money), may impede adoption and success of NOVA. Research documenting that NOVA can be implemented by consumers and has nutrition and health outcomes equal to vetted patterns is needed.

Enzymatic, physicochemical, nutritional and phytochemical profile changes of apple (Golden Delicious L.) juice under supercritical carbon dioxide and long-term cold storage

The impact of supercritical carbon dioxide (SCCD) (10-60 MPa/45 °C/30 min) and subsequent 10 weeks storage at 4 °C on polyphenol oxidase (PPO), peroxidase (POD) activities, phenolic profile, vitamin C, sugars, physicochemical properties of cloudy apple juices was investigated. No significant changes in sugars and total polyphenols were observed, whereas significant degradation (≈28%) of vitamin C and individual polyphenols (≈18%) was noted after SCCD treatment. After 4 weeks storage only 34% of vitamin C was retained and no vitamin C was detected after this time. Ten weeks of storage caused hydrolysis of sucrose in 15%, whereas degradation of individual polyphenols ranged from 43 to 50% depending on the pressure applied. The highest pressure was applied the highest retention of polyphenols was observed. The lightness of juice significantly increased by 15% after SCCD and decreased during storage. Moreover, the synergistic effect of both enzymes with chlorogenic acid and catechol was found.

Effect of pre-treatments on the antioxidant potential of phenolic extracts from barley malt rootlets

In this study, barley malt rootlets (BMR) were subjected to five different pre-treatments (steaming (220 °C), roasting (60 °C), autoclaving (121 °C), microwaving (160-800 W, 30-120 s) and enzyme treatment). Total phenolic content (TPC) and antioxidant activity of the BMR extracts were evaluated for both free and bound phenolics. The free phenolic content for non-treated extract was 1.8 mg/g of dry weight of BMR with 17.5% of antioxidant activity. Among the pre-treatments, autoclaving exhibited the highest values for free phenolics of 3.8 mg/g of dry weight of BMR and 71.6% of antioxidant activity. Pre-treatments did not show any effect on bound phenolic content, but increased antioxidant activity. The highest %DPPH activity for bound phenolics was observed for microwave treatment (160 W, 120 s) with 49.9%. Overall, pre-treatments significantly increased the free phenolic content of BMR phenolic extracts. Additional research is necessary to understand the phenolic profile and the thermal interactions of bound phenolic extracts.

Mild high hydrostatic pressure pretreatments applied before soaking process to modulate wholegrain brown rice germination: An examination on embryo growth and physicochemical properties

This investigation aimed to examine the effects of a novel processing pattern, combining high hydrostatic pressure (HHP) with germination, on the embryo growth and physicochemical characteristics of wholegrain brown rice (WBR). WBR grains were firstly subjected to mild HHP stress (30-90 MPa/5 min) and then incubated at 37 °C for 52 h for obtaining germinated samples (GBR). The results showed that HHP shock resulted in a delayed embryo growth of WBR grains, maintaining acceptable sprouting rates ranging from 65% to 76% when germination was finished. The contents of gama-aminobutyric acid in GBR were greatly increased responding to HHP stress, showing pressure intensities dependent. Total digestible and resistant starch contents in samples stressed at 60/90 MPa were decreased, mainly associated with high pressure-induced amorphization as revealed by SEM imaging and FTIR, which promoted starch hydrolysis during germination. Besides, the levels of zinc and iron were influenced by HHP pretreatments due to the high pressure-mediated degradation behavior for phytic acids. The storability of HHP-stressed GBR grains was significantly enhanced through reducing free fatty acids formation and maintaining color stability during a storage testing. These results obtained from the current work demonstrated that mild HHP stress pretreatment prior to germination process could be used as a promising strategy to modulate certain physicochemical characteristics of WBR products.

Effect of high hydrostatic pressure on background microflora and furan formation in fruit purée based baby foods

The baby foods industry is currently seeking technologies to pasteurize products without formation of processing contaminants such as furan. This work demonstrates the applicability of high hydrostatic pressure (HHP) as a non-thermal decontamination intervention for fruit purée based baby foods. HHP processing was evaluated at 200, 300, and 400 MPa pressures, for 5, 10 and 15 min of treatment times at 25, 35 and 45 °C. HHP application at 400 MPa, 45 °C for 15 min ensured complete inactivation (about 6 log₁₀) of total mesophilic aerophiles, as well as yeasts and molds. No furan was detected in HHP processed products. Thus, the key advantage of HHP over thermal processing is the ability to achieve commercially acceptable microbiological inactivation while avoiding the formation of processing contaminants such as furan.

Fundamental interfacial mechanisms underlying electrofreezing

This article reviews the fundamental interfacial mechanisms underlying electrofreezing (promotion of ice nucleation via the application of an electric field). Electrofreezing has been an active research topic for many decades, with applications in food preservation, cryopreservation, cryogenics and ice formation. There is substantial literature detailing experimental and simulations-based studies, which aim to understand the complex mechanisms underlying accelerated ice nucleation in the presence of electric fields and electrical charge. This work provides a critical review of all such studies. It is noted that application-focused studies of electrofreezing are excluded from this review; such studies have been previously reviewed in literature. This review focuses only on fundamental studies, which analyze the physical mechanisms underlying electrofreezing. Topics reviewed include experimental studies on electrofreezing (DC and AC electric fields), pyroelectricity-based control of freezing, molecular dynamics simulations of electrofreezing, and thermodynamics-based explanations of electrofreezing. Overall, it is seen that electrofreezing can enable disruptive advancements in the control of liquid-to-solid phase change, and that our current understanding of the underlying mechanisms can be significantly improved through further studies of various interfacial effects coming into play.

An Integrated Approach to Mandarin Processing: Food Safety and Nutritional Quality, Consumer Preference, and Nutrient Bioaccessibility

Mandarins are a member of the Citrus genus and are the focus of growing commercial interest, with satsuma mandarins (Citrus unshiu) and the common mandarin (Citrus reticulata Blanco) being the most important mandarin varieties. The possible health benefits and functional properties of those fruits are often associated with the antioxidative function of vitamin C, carotenoids, and phenolic compounds. While most mandarins are consumed fresh, many are processed into juices (mostly cloudy), usually via thermal processing which can lead to the creation of off-flavors and may diminish nutritional quality. The aim of this review is to summarize the most significant and recent information on the safety, sensorial properties, and nutritional benefits of mandarins and their processing into juice. The article also discusses recent information regarding the bioaccessibility of valuable, mandarin specific, compounds.